The difficulties encountered by the ten million visually impaired individuals in the United States with regard to spatial navigation are well known. Finding one's way through a bus or train station or an airport, for example, is a dramatic challenge to such a person. This navigation problem which is greatly magnified when there is a need to find a specific gate, a restroom or an agreed to meeting place. Schools, amusement parks, hiking trails, homes, hotels, residential areas, and even common sidewalks present similar difficulties to blind or otherwise visually impaired individuals.
Sighted individuals can rely on visual aids such as indicia on signs to plot paths between known and unknown places, to identify street locations, locate exits, or to determine the destination of a public transport vehicle. Consequently, this ability is generally taken for granted within the mind set of the general population and in the process of the facility design for traverse by the general population.
For the visually impaired, especially the blind, necessary facilities within residential and commercial buildings such as elevators, restrooms, escalators, or stairs have to be remembered by rote learning after repetitive trials or searched for exhaustively with the assistance of an obstacle avoidance device such as a cane, or otherwise found by asking passers by. Similar impediments to walking occur to the visually impaired in homes, trailers, hotels, and virtually any residential or commercial environment. These types of impediments not only greatly increase personal suffering and stress from what should be simple journeys, but also directly contribute to financial inequalities.
Such inequity is evidenced by the fact that only twenty-six percent of visually impaired persons are employed due to the reduced potential for searching for, and holding employment, which is generally located some distance from their place of residence. Travelers with cognitive disabilities such as dyslexia, illiteracy or retardation have similar reductions with regard to such quality of navigation. Even though the Americans with Disability Act of 1990 mandated equal access to transit and public buildings for disabled groups, the problem is far from being resolved. To date, not all street corners have curb cuts, nor do all buildings have access ramps. Further, while not all elevators or bathrooms easily lend themselves for use by wheel-chaired persons, substantial steps have been made in the public domain to meet the needs of the estimated one million U.S. wheelchair users.
Very little has been done to mitigate the trials of the ten million visually impaired persons in traveling during their daily lives. Further, little has been accomplished for the even greater numbers of those others with similar handicaps such as dyslexia, mental retardation, unfamiliarity with the language, or illiteracy, which reduces their easy access to information needed during travel or in other activities where directions are important.
As shall be seen, prior art has many examples that propose to resolve this situation. Such aids include simple devices such as a basic cane with a red tip, to others which employ buried electronic or magnetic cables or spikes and magnetic sensors. More elegant remedies have been proposed employing radar, sonar or infra-red emanations or other electrical effects to convey primarily spatial information. All fall short in that they generally consider only one component of travel. Such art appears limited to that of forward direction and course maintenance as shall be seen below in selected examples.